Reviews-^Tate 8^ Blalie — On the Yorkshire Lias. 511 



faster than the rest, united and became prolonged into a ridge ; 

 second, that the sand is carried along in lines by the wind ;, and 

 third, that these coincident ridges have been left by winds having 

 swept out parallel valleys through a mass of sand-hills formerly 

 arranged normally at right-angles to its direction. 



To sum up, the author concludes, first, that in recent geological 

 times the Runn of Kutch was part of a sea inlet extending up the 

 Indus valley and Luni river-basin ; second, the central portion of 

 the Indian Desert about Jaysalmir and Balmir was not covered by 

 the sea, but formed either an island or a promontory ; and third, that 

 the sand of the Desert is mainly derived from an old sea-coast, and 

 its transport into the interior is due to the south-west wind. 



The author writes of course from personal observation, and the 

 paper displays, as might have been expected, an intimate acquaint- 

 ance with both the zoological and geological circumstances of the 

 region. W. 



HI. — The Yorkshire Lias. By Ealph Tate. A.L.S., F.G.S., and 

 J. F. Blake, M.A., F.G.S. Illustrated by 19 Plates of Fossils, 

 a Geologically Coloured Map, Sections, and Woodcuts. 8vo. 

 (London, 1876 : John van Voorst.) 



THE volume now before us is devoted to an account of the Strati - 

 graphical details and Paleeontology of the Liassic Formation 

 of Yorkshire. Upon taking a general glance through it, we feel 

 inclined to think that if the Geology of every portion of the British 

 Islands were described and illustrated in similar detail, there would 

 be but little work left for the geologist of the future ; and the num- 

 ber of volumes too would somewhat have overcrowded the book- 

 room of most of us. Nevertheless, we are well pleased with the 

 appearance of this work — its type, arrangement, and illustrations are 

 good ; and if it had only been blessed with an Index, we could have 

 found no outward and visible fault with it. This omission in a work 

 embracing so much detail, and whose value must largely depend 

 upon its facility for reference, is indeed grievous, and we cannot 

 help remarking upon it at once. 



Hitherto British geology has been chiefly illustrated in two ways, 

 firstly, by detailed descriptions of certain geographical areas, as in 

 the Memoirs of the Geological Survey, and secondly, by detailed 

 descriptions of certain classes of organic remains, as in the Mono- 

 graphs of the Palgeontographical Society. The tracing out of the 

 stratigraphical phenomena and the illustration of the life history of 

 the rocks, when combined, form certainly the natural method of 

 recording the geological history of our country. We could have 

 wished that the entire development of the Lias had been described in 

 the volume ; but this, while it would certainly have detracted from 

 the original character of the work, would probably have placed even 

 greater difficulties than the authors have experienced, in the way of 

 publishing a volume which necessarily appeals to a somewhat limited 

 number of readers. 



The Lias as exposed in Yorkshire forms a persistent band from 



