NOTICE.

WHILE the mapping of the district was in progress, the geology of which forms the subject of this Memoir, I had several opportunities of verifying the accuracy and skill with which Mr. Judd traced the geological boundary lines, and the truly scientific manner in which he formed those deductions, the result of which has been expressed in a new classification of some of the formations comprised in the area. I may add that the circumstances which led to the resignation by Mr. Judd of his post on the Geological Survey have always been matter of deep regret to me, for it is not often that men are to be found who possess that rare combination of knowledge on so many special branches of geological inquiry which characterises the author of this memoir. I also feel that we are deeply indebted to Mr. Judd for having so frankly consented, after he had left the Survey, to make his work complete by the gratuitous preparation of a memoir which he was in nowise bound to write. That this important work has been thoroughly well done all geologists will allow. No one but the man who mapped the ground, who examined the fossils in situ, and determined so many of the species, could

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have done anything like equal justice to the subject, and the generous devotion which Mr. Judd has shown in giving so much valuable time to our work, after he ceased to be a member of the Survey, deserves the most grateful acknowledgment.

ANDREW C. RAMSAY,

13th March 1875.

Director-General.

TO THE DIRECTOR GENERAL OF THE GEOLOGICAL

SURVEY OF THE UNITED KINGDOM.

1

SIR,

Geological Survey Office,

28, Jermyn Street, London, S.W.,

20th February 1875.

THE Country comprised in Sheet 64, which takes in the whole of the county of Rutland, was surveyed by Mr. J. W. Judd, between the years 1867 and 1871.

This Map is of special interest as being the first published by the Survey upon which the limestone, that was formerly considered to be a part of the Great Oolite, has been referred to its true position in the geological scale as a member of the Inferior Oolite, to which the distinctive name of Lincolnshire Oolite was assigned by Mr. Judd, from its great development in that county.

When Mr. Judd left the Survey, on the completion of his fieldwork connected with the above area, he disinterestedly consented to write the Memoir in explanation of the Map; and the present important work is the result of his labours.

In it, besides giving a detailed description of the geological structure of the district, Mr. Judd has discussed at length the more general and purely scientific questions connected with the subject, and has explained the grounds upon which the conclusions were founded that led him to propose an entirely new and altogether original nomenclature and classification for the Oolitic rocks of the midland district of England, which have been since accepted by the Geologists of this and other countries.

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Mr. Judd has been aided by Mr. Etheridge in the preparations of the tables shewing the geographical and stratigraphical distribution of the fossils and in the palæontological portion generally. Several views of oolitic scenery have been contributed by Mr. Rutley from sketches made on the ground.

Mr. Whitaker has also assisted in the bibliographical portion; and Mr. Holloway has rendered valuable help in constructing and drawing illustrative geological sections, as well as generally in passing the work through the press.

I have the honour to be,

Sir,

Your obedient servant,

HENRY W. BRISTOW,

Director for England and Wales.

To Andrew C. Ramsay, Esq., LL.D., F.R.S.,