Mr. H. J. Carter on known Fossil Sponges. 285 



viz. Pachastrella primceva, Tethr/opsis 8teinmanni, P. convo- 

 luta, and P. plana-^ihe former two by Zittel (Foss. Spon(^. 

 I. c. p. 100, Taf, xi. figs. 3 and 4) and the latter two by Dr. 

 Hinde (Cat. Foss. Spong. Brit. Mus. p. 26, pi. ii. figs. 1, 1 a, 

 and pi. i. figs. 7,7 a respectively). 



This brings lis 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 — 

 Auhcopium, A. aurantinm, Zitt. [op), cit. p. 136, pi. viii. 

 fig. 1, and ' Handbuch,' pp. 159, 160, fig. 72 a) ; also Hindia, 

 Hinde, //. fibrosa (Cat. Foss. Sp. Brit. Mus. p. 57, pi. xiii., 

 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. CI. xiii. 

 Bd. i. Abth. pp. 67 6cc. ; translated into the ' Annals ' by W. 

 S. 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. 



Happening 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 Beak 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 &c. 

 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 Ujiper 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 sulDJect in the ' Annals ' 

 of 1871 (vol. vii. p. 112, pis. vii., viii., ix., and x.). 



Tliat many originally came from the spiculiferous sponges 

 of my Orders IV., V., and VI. generally, may be fairly 



