127 
Somerset, and from which I have obtained an almost identical 
series of species, with Terebratula sphaeroidalis. Its litholo- 
gical character is somewhat different, but otherwise in its 
fauna it is the bed south of the Mendips, which has more 
resemblance to its Cotteswold equivalent of the same age than 
any other Inferior Oolite bed which I know, except, perhaps, 
those with Am. opalinus. Mr Witchell gives the thickness of 
the Upper Trigonia grit at Stroud Hill at 6 feet, and at Rod- 
borough 4 feet. Above he mentions a Coral bed, 4 feet at the 
former and 38 feet thick at the latter place. I cannot say if 
the upper of the beds which I have placed in the Trigonia grit 
be the equivalent or no, but I have not noticed any evidence to 
cause me to think so. 
Above the Trigonia Grit we meet with what is known as the 
Clypeus grit, which, in the first cutting west of Notgrove 
Station, exhibits a depth of 36 feet, probably the greatest 
development known. The beds, too, are fairly uniform in com- 
position, and in this as well as in thickness offer a remarkable 
contrast to Rodborough, which, according to Mr Witchell,* con- 
tains two beds of Clypeus Grit, 5 feet 6 inches, hard brown 
Limestone, two feet, and brown sandy Grit, two feet, above the 
Coral bed, which overlies the Upper Trigonia Grit. In the 
district we are treating of, the Clypeus Grit is generally of a 
rather rich yellow colour, and of the character of a loose dis- 
connected sort of Ragstone, with an occasional resemblance to 
soft Freestone. In some places blue marly seams occur, but 
of no great extent. Terebratula globata and its numerous 
varieties are to be frequently met with throughout the whole 
series. In section VII. there occurs a peculiar bed of a kind 
_ of decomposed paste, and in this occurs a peculiar variety (?) of 
Tereb. globata, with its valves much thickened at the margin, 
and with very small folds. Clypeus Plottii occurs more or less 
throughout this grit, but it is usually more abundant in the 
upper part, and when the line was first made and ballasted, any 
quantity of large specimens could be seen lying loose, though 
generally with more or less shell detached. The presence of 
® Geology of Stroud, p. 55. 
