438 MR. L. RICHARDSON ON THE INFERIOR OOLITE [j^OV. I907, 



Above the Marlstone is the Upper Lias, a clay-formation from 

 top to bottom — at Little Eissington about 100 feet thick, and near 

 Milton (teste Prof. E. Hull) about 20 feet. 



Upon the Upper Lias rests the Glyjpeus-Grit subdivision of the 

 Inferior Oolite. All the intervening beds, which at Leckhampton 

 Hill measure something like 200 feet (and on the Cleeve-Hill 

 plateau considerably more), are absent. 



Briefly, the explanation of their absence is as follows: — The 

 Moreton Valley marks a line of weakness. Some Inferior-Oolite 

 beds that were probably deposited across it have been anticlinally 

 disposed and removed, and others have thinned out in its direction. 

 Elevatory movements were doubtless of frequent occurrence, and it 

 is improbable that the Inferior Oolite deposited across the axis ever 

 attained any considerable thickness. 



Just before the Upper Trigonia-Grih was laid down, there 

 occurred crust-pressures as severe as any that took place in 

 Inferior-Oolite times. In the Cottes wold-Hill district the beds 

 were thrown into a number of slight anticlines and synclines. 

 The maximum removal of deposit naturally took place in the 

 neighbourhood of the anticlines, and as the Moreton anticline was 

 one of the principal axes of elevation, it is not surprising to find 

 that there is no pie-Garantiance Inferior-Oolite deposit left in its 

 immediate neighbourhood. In the Eissington district the Upper 

 Trigonia-Grit is missing as well. It may have been deposited and 

 removed by a relatively-slight erosion that took place in some parts, 

 while the Dundry Freestone was being formed over a restricted 

 area in Northern Somerset, and the Upper Coral-Bed over a far more 

 extensive area ; but, on the other hand, it may never have been 

 deposited at all in the neighbourhood of the Kissingtons, owing to 

 the insufficient submergence of the area in the Garantiance hemera. 



At the present time — at all events, in the district under con- 

 sideration — the Clyjoeus-Giit rests directly upon the Upper Liassic 

 olays. 



II. Comparison op the Inferior-Oolite Deposits of the 

 Bath-Dotjlting and Eissington-Btjrford Districts. 



In the Bath-Doulting district the Upper Trigonia-Grit rests 

 directly, and therefore non-sequentially, upon the Upper Lias ; in 

 other words, the Bathonian and Toarcian are in apposition, and the 

 whole of the Bajocian and Aalenian are absent. In the more 

 immediate neighbourhood of the Mendip Hills the Doulting Stone 

 oversteps on to the Carboniferous rocks. 



In the Dundry-Timsbury-English Combe area, above the Upper 

 Trigonia-Grit comes the Dundry Freestone, the geographical extent 

 of which is inconsiderable. The Freestone is succeeded by the 

 Upper Coral-Bed, which overlaps it. Above the Upper Coral-Bed 

 are the following subdivisions, with their leading fossils indicated 

 alongside : — 



