40 



THE GEOLOGIST. 



drainage of nine thousand one hundi-ed and seventy three square miles, of which 

 the Trent alone draws from four thousand five hundred square miles, the re- 

 maining four thousand six hundred and seventy-three square miles supplying 

 the Ouse, we may form some idea where part of the " warp" comes from. 

 What proportion river-sediment from floods, etc., may supply, I cannot pretend 

 to say. Then we have the gradual wearing away of our Yorkshire coasts from 

 two miles east of Bridlington Quay to Spurnt Point, which is a distance of 

 about forty-three miles. Along this coast we lose, on an average, six feet 

 three inches annually. In fact new roads have continually to be made in con- 

 sequence of the sea making such rapid encroachments on the land, which, when 

 washed away, is taken up the Humber and constitutes another source from 

 which the " warp" is formxcd, and deposited upon lands up the rivers, etc. 



I think your correspondent, W. Nottingham, will be able to draw from 

 these facts answers to both his questions. I believe that no other river, or 

 rivers in England are situated under such favourable circumstances for making 

 the deposits called " Avarp" as are the rivers above mentioned. — Dear sir, yours 

 faithfully, Edwaed Tindall. 



REVIEW, 



Mr. Tennanfs Mineralogical and Geological Collections. 



We have received specimen cases of the two hundred, and three hunth-ed 

 selected examples of fossils and minerals, accompanied by the very useful cata- 

 logue of ordinary British fossils, recently published by Mr. Tennant. These 

 collections are designed as an mitiary means of instruction for students and 

 tyros. Nothing so much tends to facilitate and encourage the study of any 

 science as a ready means of access to the principal objects referred to in the 

 general descriptions and writings of authors. It is easy to accumulate speci- 

 mens of rocks and fossils, and to form expensive collections ; but it is not so 

 easy to form a limited and proper selection which shall at once illustrate the 

 chief facts of a science, and be of real service to the student. 



Professor Tennant's well known intimate knov/ledge of minerals gives confi- 

 dence to learners as to the correctness of the naming of the specimens, and his 

 long experience in this class of rudimentary collections — first made by his im- 

 mediate predecessor, Mr. Mawe, more than fifty years ago — shows itself in the 

 completeness and perfection of the present cabinet collections, in which, al- 

 though the samples of fossils and minerals are of small size they are typically 

 characteristic, and have every scientific advantage of displaying sufficiently 

 their characters with that essential one of condensed space. The cabinets in 

 which the collections arc contained are strongly and neatly made, and, whether 

 as useful and interesting presents at this season of gifts, or viewed in their 

 pro])er light of aids to the comprehension of elementary treatises on Geology 

 or Mineralogy, they are well worthy of the recommendations given to tbeni by 

 Sir Charles Lyell, the late Dr. Mantell, and other eminent geologists, and iu 

 which we readily concur. 



