418 Reviews—C. Fox-Strangways— 
favour of regarding all the beds above the Lower Calcareous Grit 
and below the Kimeridge Clay as parts of one system. 
The zone of Am. plicatilis is held to include the Middle Calcareous 
Grit, where these beds are developed, as in the Hambleton and 
Tabular Hills, the Upper Limestone, and the Upper Calcareous Grit, 
together with its equivalent, the Cement-stone Beds of the eastern 
portion of the Howardians. As a matter of fact the Upper Cal- 
careous Grit is non-existent in the Howardians, since the unexpected 
and exceptional development of Upper Calcareous Grit at Coxwold 
can scarcely be placed in this system of hills. The delimination 
of the Middle Calcareous Grit forms an important part of Mr. 
Strangways’ work, the more so as the existence of this independent 
arenaceous series was never suspected by Phillips and the earlier 
geologists. He enumerates the fossils of the Trigonia-beds at 
Pickering along with those of the Middle Calcareous Grit, and 
notes the possibility of this horizon occurring at Middle Cave, near 
Malton, although it would, of course, be impossible to indicate on 
a map anything like Middle Calcareous Grit in the Howardians. 
In dealing with the inner margin of calcareous rock which girdles 
the Vale of Pickering he indicates the possibility of a separate origin 
for the Coral Rag of the Ayton district from that of Pickering and 
the westward. The Coral Rag, in its typical form, rather fails 
about Pickering, being possibly represented by obscure calcareous 
beds, but as we go westwards towards Oswaldkirk a great variety 
of Coral-rock obtains and the sides of the quarries often present 
beautiful arabesques where the structure has been brought out by 
weathering. On the opposite side of the Vale, at North Grimston, 
the Coral Rag would seem to have attained its maximum develop- 
ment, but rapidly thins out southwards to complete extinction. The 
relations of this rock to the overlying cement-stone, chiefly formed 
from its denudation, and of both of them to the Kimeridge Clay 
above and the Lower Calcareous Grit below, constitute an episode 
in stratigraphy which renders the Birdsall district one peculiarly 
difficult of interpretation. 
The Upper Oolites are dismissed somewhat briefly, one chapter of 
a dozen pages being all that is devoted to their consideration. 
Practically, the Upper Oolites in Yorkshire consist of the Kimeridge 
Clay, since the beds, recently distinguished as the zone of Bel. 
lateralis, have no title to be considered Portlandian, though they may 
possibly represent in time a portion of the Purbeck series. 
It would seem that the mystery which has so long attached to 
the Kimeridge Clay of Yorkshire is still unsolved, and that no 
conclusive information is available as to what underlies those portions 
of the Vale of Pickering which lie between the great bounding 
faults. Mr. Strangways questions how far it is possible to trace 
the accepted divisions of the Kimeridge Clay in Yorkshire, the 
outcrop being usually covered by alluvium, “so that it is only in a 
few obscure sections in Filey Bay, at a few places towards the 
western end of the Vale of Pickering and along the western escarp- 
ment of the Wolds, which is much slipped and confused, that we 
get exposures of the beds.” 
