326 SCIENCE PROGRESS. 



But little has been added to our knowledge of the Trias 

 in Northern Europe. Stizenberger (35) has described the 

 rocks exposed on the railway between Koblenz and Stein ; 

 but they offer no points of special interest. 



JURASSIC. 



The most important contributions to Jurassic geology 

 come from our own country ; and we must first draw 

 attention to the monograph by H. B. Woodward (41) on 

 the Lias of England and Wales (exclusive of Yorkshire, 

 which has already been treated by Fox-Strangways 1 ). 

 This work is too extensive and too much occupied with 

 local detail to admit of useful abstract here. It is more 

 particularly concerning the south-western parts of England 

 that new facts will be found in it. At the end is a list of 

 fossils from the English Lias (exclusive of those which occur 

 only in Yorkshire, north of the H umber) ; and it is worthy 

 of note that the well-known Gryphea incurva appears as 

 G. arcuata, a name which certainly has priority, and which 

 is commonly used abroad. 



In the district between Sherborne in Dorsetshire and 

 Yeovil in Somersetshire S. S. Buckman (7) has made a 

 detailed examination of those beds of the Inferior Oolite 

 which are usually known as the zones of Ammonites 

 Murckisonte, A. Sowerbyi, A. Humphriesianus, and A. 

 Parkinsoni. But the author is far from being content 

 with this grouping, and he subdivides the period of deposi- 

 tion into twelve smaller divisions which he calls " hemera^ ". 

 By a hemera he understands the period of time during 

 which a certain species was at its acme of development ; 

 and each of his twelve hemera± is characterised by its 

 own ammonite. 



The area described is only some eight miles in length, 

 and yet within this distance the deposits of the hemera of 

 A. Garantiance, for example, vary from less than a foot to 

 thirty feet in thickness. Among the other deposits the 

 variations are also very great, and the author shows them 



lr The Jurassic Rocks of Britain, vols i. and ii. Mem. Geo/. Sun'. 



