A. K. Coomdmsivdmy — Radiolaria in Oondiodna Beds. 305 

 The types at present missing from this collection are : — 



V. — OCCURKENCE OF EaDIOLARIA IN GoNDWANA BeDS NEAR MADRAS. 

 By A. K. CooMAKASWAMY, B.Sc, F.L.S., F.G.S. 

 (PLATE XVII, Figs. 1-6.) 

 rpHE Upper Gondwana (Eajmahal Series) beds near Madras are 

 1 divided into two groups, the lower of which has been named 

 from Sripermatur, a town 25 miles west-south-west of Madras, and 

 a well-known locality for fossil plants. The group is composed 

 of white and pale buff-coloured shales containing plants, at least 

 10 feet in thickness, resting upon sandstones, grits, and micaceous 

 sandy shales, at least 15 feet in thickness, whose base is not seen, 

 but which probably rest on the gneiss. Silicified wood occurs in 

 some of the gritty beds. The other fossils occur in the shales, 

 and consist of plant and animal remains. The latter are poor, 

 and comprise two or three indeterminable species of ammonites and 

 several lamellibranch bivalves. 



Last year, while staying at Madras I paid a short visit to 

 Sripermatur, accompanied by Mr. Ranga Chari, M.A., of the Madras 

 University. I did not obtain many plant-remains, but was struck by 

 the very porcellanic character of the shales containing them. These 

 are thin-bedded, white to cream or pale coffee-coloured, and often 

 have a smooth conchoidal fracture. A few specimens were collected 

 from a wayside exposure, on the track between Sripermatur and 

 Vellum. In the thin slices cut from these specimens Eadiolaria 

 are to be seen, though for the most part in a very poor state of 

 preservation. These organisms, together with tiny fragments of 

 clastic quartz, and rarely a few carbonaceous specks, are embedded 

 in a fine siliceous paste which remains dark between crossed nicols. 

 Quite locally chalcedonic patches show a fibrous structure. The 



^ This species is described mthout a figure : the tjrpe is said to be iu the ]\Iuseum 

 of the Academy of Natural Sciences, PhfladelpMa. 



DECADE IV. — VOL. IX. — NO. VII. 20 



