1859.] PHILLIPS GREAT OOLITE OF THE CHERWELL. 115 



comparative study of species. I shall be happy if the materials 

 which are being collected in my work shall in any way contribute to 

 this. 



Note by C. J. F. Bunbury, Esq., F.G.S. 



As I am at present engaged in a thorough examination of the 

 fossil plants (supposed to be Jurassic) from India, in the collection 

 of the Geological Society, and as I hope to lay the results of this ex- 

 amination before the Society in its next Session, I shall defer to a 

 future time the discussion of several questions raised by Sign, de 

 Zigno. I will merely observe at present, that I have great doubts 

 whether any of the species of fossil plants found in the Indian beds 

 are identical with those of Yorkshire. Certainly I have not yet seen 

 any that are so. 



Sign, de Zigno quotes me as authority for the statement that the 

 Ghssopteris of India has been found with a digitated frond like that 

 of Sagenopteris. I must observe upon this, that this fact does not 

 rest on my own observation. I merely mentioned in my letter that 

 I had heard that the digitated form of frond had been observed 

 in Australian (not Indian) specimens of Ghssopteris Browniana. 

 Among the numerous specimens of Ghssopteris, of more than one 

 species, both from India and from Australia, which I have now had the 

 opportunity of examining, I have not been able to discover any in- 

 dication of such a structure. The question, whether Ghssopteris and 

 Sagenojiteris are sufficiently distinct as genera, is open to discussion ; 

 but, if it should be found advisable to reunite them, the name of 

 Ghssopteris, as the older and quite unobjectionable, ought un- 

 doubtedly to be retained. — March 1859. 



4. On some Sections of the Strata near Oxford. 



By John Phillips, M.A., LL.D., F.R.S., Pres. Geol. Soc. 



No. 1. The Great Oolite, in the Valley of the CherweU. 



The value of exact records of the peculiarities of local sections is 

 strongly felt by every geological reasoner who touches problems of 

 the distribution of oceanic sediments, the boundaries of land and 

 sea, the mixture or alternation of fresh and Ball water, or the local 

 origin and geographical diffusion of particular forms of life. This is 

 specially found to be the ease while considering the lines of contem- 

 poraneity in the mesozoic strata of England, in which the influences 

 of diversified tracts of land and lines of shore, and of unequal sea- 

 depth and varying currents, are complicated by ineqnalitiee in the 

 duration of the several groups of organic remains. 



In the district immediately surronnding Oxford, sections illus- 

 trating these causes of local diversity may have more than ordinary 

 interest at this juncture. Binoe here BOme of the Oolitic strat a are 



supposed to die out, while below them the Upper I.ias. and above 



VOL, xvi. — PAST I. K 



