Mr. H. J. Carter on known Fossil Sponges. 285 
viz. Pachastrella primeva, Tethyopsts Steinmannt, P. convo- 
luta, and P. plana—the former two by Zittel (Foss. Spong. 
l. c. p. 100, Taf. xi. figs. 3 and 4) and the latter two by Dr. 
Hinde (Cat. Foss. Spong. Brit. Mus. p. 26, pl. i. figs. 1, La, 
and pl. 1. figs. 7, 7 a respectively). 
This brings us to the other division of the Pachastrellida, 
viz. the Lithistina, which in time and space so far surpasses 
any other group of sponges, extending from the Silurian— 
Aulocopium, A. aurantium, Zitt. (op. cit. p. 136, pl. vill. 
fig. 1, and ae pp- 159, 169, fig. 72 a) ; also Hindia, 
Hinde, HH. fibrosa (Cat. Foss. Sp. Brit. Mus. p- 57, pl. xii., 
and for spiculation, ‘ Annals,’ 1887, vol. xix. p. 76, figs. 1 
and 2)—down to the present day inclusively, but abounding 
most in the Oolitic and Cretaceous periods, as may be 
seen by reference to the table in Prof. Zittel’s ‘ Study on 
Fossil Sponges,’ more particularly given in his illustrated 
descriptions (Abhandl, der k. bayer. Akad. der W. ii. Cl. xii. 
Bd. i. Abth. pp. 67 &c. ; translated into the ‘ Annals’ by W. 
8. Dallas, F.L.S., in 1878, vol. ii. pp. 113, 235, 324, 385, and 
467 respectively), wherein an amount of sagacity and ability 
is exhibited that is almost beyond all praise. 
Happenimg to reside in a locality (viz. Budleigh Salterton, 
on the south coast of Devon) where the hardened remains of 
the Upper Greensand and Chalk, which once extended across 
the country for many miles between “ Haldon Hill” on the 
west and ‘‘ High Peak Hill” on the east, now bestrew the 
surface in great abundance, I can state from actual observa- 
tion that almost every chert-flint contains the remains of a 
Lithistid sponge or consists of chertified Lithistid spicules &e. 
in layers which once formed the bed of an ocean, so abundant 
were these sponges at that period. 
Thus it would appear that the maximum development of 
Lithistid sponges took place during the Upper Cretaceous 
period, although the existing species are still very numerous. 
Among the : separate spicules which are so abundant in the 
Upper-Greensand chert may also be seen those of many other 
sponges, especially those of Geodina, whose little siliceous 
spheroids seem to be always present in great numbers. In 
the Upper Greensand of ‘ Haldon Hill,” near Exeter, where 
there is a bed several feet in thickness composed of grains of 
sand and sponge-spicules, these ingredients are so loosely 
held together that the latter can be easily picked out, as may 
be seen by my illustrated paper on the subject in the ‘Annals’ 
of 1871 (vol. vii. p. 112, pls. vii., viil., ix., and x.). 
That many originally came from the spiculiferous sponges 
of my Orders IV., V., and VI. generally, may be fairly 
