550 Prof. Gariuood — Calcareous Alga.. 



The examples of Solenopora met with in the Great Oolite ^ and 

 Coral Rag are of special interest. In both cases they attain very 

 much larger dimensions than any species yet discovered in the 

 Palaeozoic rocks. 



At Chedworth, near Cirencester, I have collected masses of Soleno- 

 pora Jurassica, measuring up to a foot across, in which the original 

 pink tint is still so conspicuous on freshly fractured surfaces as to 

 give rise to the local appellation of ' Beetroot Stone ', and the colour 

 also reminds one of the red algae growing in great profusion at the 

 present day in the Gulf of Naples. 



It is also recorded from the same horizon by Dr. Brown* from 

 near Malton in Yorkshire, and also, on the authority of the late 

 Mr. Fox Strangways, by Rothpletz.^ 



In Yorkshire, however, one form undoubtedly occurs at a higher 

 horizon, namely, in the Coral Rag of the Scarborough district, where 

 it is well known to local collectors. Specimens which I have 

 collected from this horizon at Yedmandale and Seamer also attain 

 a considerable size — up to 3 inches in their longest dimension. 



The name Solenopora Jurassica was given by Nicholson in manuscript 

 to specimens from Chedworth, and was adopted by Dr. Brown in his 

 description of the specimens from both Chedworth and Malton in 

 Nicholson's collection. 



Rothpletz points out that specimens examined by him from York- 

 shire differ from the genotype in the fact that the cells are typically 

 rounded in cross-section and by the absence of perforations in the 

 cell-walls, and he therefore proposes to separate it as a new genus 

 Solenoporella. It seems probable that some confusion has arisen 

 between the specimens to which Nicholson originally gave the name 

 of S. jurassica from the Great Oolite of Chedworth and other 

 specimens from Malton from a higher horizon'' — the Coral Rag. 

 I have collected specimens from both horizons and consider that the 

 Chedworth specimens, to which the name Solenopora jurassica was 

 originally given, represent a species of true Soletiopora, showing 

 closely packed cells with polygonal outline in tangential section ; the 

 form from the Coral Rag of Yorkshire, with distinct circular outline 

 to the tubes in tangential section, is specifically, if not generically 

 distinct, and is that described by Rothpletz as Solenoporella. 



If this view be correct we should continue to speak of the 

 specimens from the Great Oolite at Chedworth as Solenopora jurassica, 

 while those from the Coral Rag of Yorkshire must be known as 

 Solenoporella sp., Rothpletz. 



' Foreign Jurassic. 



In foreign Jurassic rocks the recorded occurrences of Calcareous 

 Algae are surprisingly few. 



Quite recently, however, Mr. H. Yabe* has described a new species 

 of Solenopora, under the title Metasolenopora Rothpletzi, from the 



1 Proc. Cot. Nat. Club, vol. x, p. 89, 1890. 



2 Geol. Mag., Dec. IV, Vol. I, pp. 145 et seqq., 1894. 



' Kungl. Svenska Vet. Akad. Handl., Bd. xliii. No. 5, 1908. 



■* See Fox Strangways, Geol. Mag., Dec. IV, Vol. I, p. 236, 1894. 



^ Sci. Eep. Tahoku Imp. Univ. Japan, 1912. 



