24 
extension of the Pea Grit over the Stroud area having been 
overlooked by Lycrerr and others. Lycrrr noticed the bed of 
Pea Grit at Selsley, (p. 41) which he described as a band of 
marl, and although he alluded to the abundance of Terebratula 
plicata in the bed, he never noticed the sections of Nerincea which 
the face of the rubbly rock exhibits. So with respect to the beds 
of Pea Grit at Longfords, near Nailsworth, which are minutely 
described, (p. 42.) The concretionary bed has the appearance 
of a brown marly limestone, in which there are large pisolitic 
grains; it contains several species of Nerinwa in great abun- 
dance. Lycrrr has placed these beds in the middle or Freestone 
division of the Fimbria stage,—having previously described the 
Pea Grit of Leckhampton and Birdlip in the lower division of 
that stage. It may be said, in explanation, that in the vicinity 
of Nailsworth and Selsley the Pea Grit has lost much of its 
distinctive character, the pisolites are much smaller than at 
Birdlip, and the beds are approaching their termination in 
that direction, so that unless their continuity had been traced 
throughout the whole area, their true character and strati- 
graphical position might, without much want of care, have 
been, as they were in fact, overlooked; but if Lycrrr had 
suspected that these beds were the extension of the Pea 
Grit of Birdlip, he would undoubtedly have examined them 
more closely, and have discovered that they were full of 
Nerineas. 
In the Stonesfield Slate Professor Buckman discovered one 
species, and Lyczrt one, and in the Great Oolite five others; to 
these I have recently added four, making in all eleven Great 
Oolite species. So that we have in the Great and Inferior 
Oolite of the Cotteswolds at least thirty-one species if not 
many more. 
If we were to classify these species from their internal 
structure alone, we should find that they consist of five groups, 
namely :— : 
(1.) Those which have one fold only on the outer wall, and 
are the simplest in structure of the genus. They are— 
N. gracilis, Lyc. Inf. Oolite (Marly Limestone.) 
N. calearea, (Syn. N. simplex) Witc. G. Oolite (White limestone.) 
