7.  Extending the Survey of Britain

The Ordnance Geological Survey, 1835

From the very start of De la Beche’s first surveys there was an understanding that it might in due course be extended to other parts of the country.

This understanding is reflected in the 1832 correspondence recorded in the Ordnance Survey letter books. It was also widely reported, prompting at least one provincial geologist to recommend his mapping skills to the Board of Ordnance.

Thus, Dr Henry L. Boase of Penzance wrote to the Board on 30 June 1832 offering his services to ‘delineate on your Map, the various rocks and the principal metalliferous veins of Cornwall’ (GSM 1/68, 80-2).

Colby advised the Board that it would be wise to defer a decision on Dr Boase’s offer until the Devonshire survey had reached a more advanced state.

In the event, nothing further seems to have transpired respecting this offer. Dr Boase’s competency as a geological observer was brought into disrepute in 1834 following the publication of an ambitious Treatise on Primary Geology and the reading of a paper at the British Association meeting in Edinburgh, where he showed himself to be ill-informed about the difficulties of interpreting the older rocks of south-west England (Rudwick 1985, 88–9).

On 25 May 1835, De la Beche wrote to the Board to announce ‘that the Geological Map of Devonshire, with portions of the adjoining counties ... executed in compliance with the order of the Honble. Board of the 2nd May 1832, is now completed...’ In concluding his letter he expressed the hope ‘that the Honble Board will be pleased to examine the result of my labors; and if they shall find that it is desirable to continue the Geological Survey, I would willingly devote my time to the Geological examination of another portion of country’ (GSM 1/68, 93).

The Board wasted no time in calling upon the President of the Geological Society (at that time Charles Lyell), and two of its most prominent and respected members, William Buckland and Adam Sedgwick, to report on De la Beche’s work and on the expediency of extending the survey to other parts of the country.

Devonshire Survey

The Society’s report, dated 12 June, was full of praise: ‘Our opinion is that the execution of the geological survey of Devonshire is the result of great labour combined with great skill, and that no geological Map of such extent has been published in Europe equal to it in the minute accuracy of its details.

We regard its publication as reflecting great honor on the Board of Ordnance, with whom it originated, and at the same time as a benefit to European Science.

We are further of opinion, from this evidence, but still more from our personal knowledge of the unusual combination of qualifications which are united in Mr. De la Beche, that it would be highly honourable and useful to the Nation to continue his services, in the extension of a geological survey on one uniform system over other parts of Great Britain’ (GSM 1/68, 98).

Economic advantages of geological maps

The report goes on to examine the economic advantages of good geological maps ― these are:

  1. to aid the search for coal and metals, and thereby reduce wasteful speculation;
  2. to locate the best materials for making and repairing roads;
  3. to indicate the situation in which water may be obtained at the least expense in sinking wells;
  4. to assist in the construction of canals, rail-roads and tunnels;
  5. to indicate where good limestone, brickearth and building stone may be encountered; and
  6. to support agriculture by pointing to the occurrence of lime, marl, gypsum and other materials for the artificial improvement of soils.

The foregoing is expressed in similar terms to that of an undated note written by De la Beche some time before 1835 (North 1936, 47-8).

In terms of organisation, the report advised the establishment of a subordinate branch of the Ordnance Survey under the control of Thomas Colby, consisting of De la Beche and any assistants that might be considered expedient.

It was recommended (on the advice of Colby) that De la Beche receive a salary of £500 per annum, together with £1000 to cover the appointment of assistants and for defraying other contingent costs.

Treasury approval

On 18 June the Master General of the Board of Ordnance gave approval for the recommendations to be carried forward for Treasury authorisation.

The Treasury responded favourably on 30 June, stating that ‘they will cheerfully give their sanction to any measure which may facilitate so desirable a result, if it can be obtained at a moderate expense.’

With this last consideration in mind the Treasury not unreasonably asked the Board for an ‘Estimate of the time which they consider will be required for the entire completion of the whole undertaking’ (GSM 1/68, 107).

The question was referred to De la Beche who replied on 4 July that ‘In answer to your question respecting the time required to complete the Geological Survey of Great Britain, I beg to state ... that depending as it must do upon the amount of competent aid which I may receive ... I consider that the Geological Map will keep pace with the Geographical Map, and consequently that both Maps will be completed at the same time’ (GSM 1/68, 113).

Figure 15. De la Beche’s copy of a letter from Colby to the Office of Ordnance, requesting an imprest of £100 to be granted to De la Beche in respect of  his appointment on 11th July 1835 (Reproduced courtesy of the Department of Geology, National Museum of Wales, NMW 84.20G.D.261).

Unsurprisingly, the Lords Commissioners of the Treasury were not about to be disarmed by a cleverly evasive response.

Francis Baring, Secretary to the Treasury, asked De la Beche privately for an estimate of the time required ‘to perfect the Geological Survey of that part of England and Wales which has already been completed by the Ordnance.’

How long would it take to survey Britain?

De la Beche replied that it would take 21 years to survey the current 66 Ordnance sheets, assuming that he worked singly and was unassisted.

If, however, he received the aid of two or three competent assistants, as was envisaged, and was able to purchase local information as occasion might require, he could complete the geological mapping of the published part of the Ordnance Map in only seven years.

On this basis he estimated that, with the necessary aid, ‘the Geological Map of England and Wales may be completed in about ten years’ (GSM 1/68, 119–20). It would be surprising if De la Beche believed this to be a realistic estimate, and he certainly changed his mind a few years later.

Behind the scenes, De la Beche was doing everything he could to ensure a successful outcome to the Treasury decision. He asked Sedgwick to use his personal influence with both the Marquis of Lansdowne, Lord President of the Council and a prominent supporter of science, and Thomas Spring-Rice, Chancellor of the Exchequer.

Worsening finances

De la Beche's financial situation had worsened during 1833–34 owing to a further decline in the value of West Indian property, while his fee for the Devonshire survey had not even covered his expenses (Rudwick 1985, 103, 125). De la Beche’s livelihood was now very much in the balance.

Relief arrived when De la Beche was forwarded a written communication from the Board of Ordnance, dated 11 July 1835 and addressed to the Inspector General of Fortifications (under whose control the Ordnance Survey resided), which informed him that the Treasury had sanctioned a ‘Geological Survey of Cornwall.’

The Lords Commissioners still felt that his estimate of expenditure for the whole survey was ‘insufficiently ascertained’, but hoped that a better estimate of the annual rate of progress and expense might be obtained following the completion of the Cornish survey (GSM 1/68, 117–8).

With this letter of appointment the Geological Survey as an institution may be said to have been born (Figure 15). As a branch of the Ordnance Trigonometrical Survey it assumed the title of ‘Ordnance Geological Survey,’ under the overall control of Lt-Col. Thomas Colby.

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Bate, D G.   2010  Sir Henry Thomas De la Beche and the founding of the British Geological Survey.  Mercian Geologist, 17 (3). 149–165.