Reviews — Dr. Roice on the White Chalk of Yorkshire. 233 



As the autlior expressly disclaims that his paper should be taken 

 ?»s more than "a preliminary attempt to bring the fauna of the 

 Yorkshire coast into line with that of our southern sections," and 

 as he has so successfully achieved this object, it would be both 

 unjust and ungrateful to consider his work in any other light. Now 

 that the way is made clear we shall expect that the group of 

 persistent investigators dwelling in the East Riding will push 

 forward the work with renewed energy, not only testing what has 

 been done but also adding to it where necessary. Especially should 

 we like to hear of the establishment of local zones of less extensive 

 dimensions than those which Dr. Rowe has given us. The value 

 of a narrow zone to the stratigrapher was strikingly manifest in the 

 above-cited instance at the Buckton overthrust fault. Here the 

 author had the advantage of having to deal with the only narrow 

 zone in his category — that of Bhynchonella Cuvieri. The thickness 

 of this zone in the Buckton cliffs is no more than 11 feet, whereas the 

 next in dimensions, those of Micraster cor-testudtnarium and M. cor- 

 anguinnm, are given as 120 feet and 125 feet; and all the others 

 range between 200 and 300 or more feet. Moreover, even with 

 such extensive bounds allotted to them some of the zonal forms 

 are still not content, but manage to invade their neighbour's territory. 

 Thus we learn that " Holaster planus is as common in Yorkshire in 

 the zone of Ter. gracilis as at its own horizon." Faults of considerable 

 magnitude may remain undetected in the interior unless we can find 

 means to identify belts of strata of much narrower limits. Indeed, 

 we are reminded by the coloured map which accompanies Dr. Rowe's 

 paper of a long-standing suspicion that there is likely to be some 

 disturbance of the normal succession at Speeton between the railway 

 line and the coast, to which the pinching in of the zones in this 

 quarter may be due; and the reviewer would recommend this area, 

 with the country to the south and west, to further consideration. 



The Cenomanian or ' Lower Chalk ' in this as in his former papers 

 does not come within the range of Dr. Rowe's investigation. We 

 think, however, that it would have been well at least to include it 

 in giving estimates of the total thickness of the White Chalk of 

 Yorkshire, since in this region the division is essentially part of the 

 lithological mass which we mean when we refer to the ' Yorkshire 

 Chalk.' Moreover, this part of the series had previously been worked 

 out with great care by Mr. W. Hill, so that accurate measurements 

 were already available. It is true that passing reference is made 

 to Mr. Hill's paper, but there would have been a distinct advantage 

 if we had had a few sentences giving a summary of this work in 

 the present publication, so that some account of the whole section 

 might have been contained under one cover. 



The lavish wealth of illustration to which Dr. Rowe has ac- 

 customed us in his previous works is again granted to us and 

 deserves our gratitude. The magnificent series of photographic 

 reproductions (in most cases from originals for which the author 

 tenders his acknowledgments to Professor H. E. Armsti'ong) brings 

 up vivid reminiscences of this noble coastline. 



