I860.] rniLLiPs — sections near oxford. 311 



apparently corresponding with those of Shotover ; and these rest on 

 the Kimmeridge Clay, but grow thinner and die out to the southward. 



Another example of a sandy deposit covering the Kimmeridge 

 Clay occurs at Toot Baldon, a village elevated above the general 

 plain of Kimmeridge Clay, and lying four miles north-east of Culham. 

 Here, some years since, on the very summit I found sandy and 

 stony beds in small quantity and not well exposed. They yielded 

 me no fossils ; but my friends of the Geological Survey have since 

 visited the locality, and obtained an Ammonite which they believed 

 to be of the group of A. Deshayesii *. I lately re-examined the spot, 

 now less exposed than ever, without finding anything satisfactory. 

 ]>ut on proceeding down the sloping road to the eastward, I per- 

 ceived the clay to be there also covered by ferruginous bands, and 

 commenced a persevering search for fossils. I made a considerable 

 excavation, and obtained several shells, especially a My a, Pectin, 

 Cardium, Trochus, and an Ammonite which appears to be of the 

 group of A. poh/jplocus, A. triplicatus, and A. giganteus. 



The mass is sand and sandstone with small black pebbles, and 

 stained very brown by oxide of iron. It rests immediately on the 

 Kimmeridge Clay, probably on the very top or upper layers. In the 

 hope of revisiting this place and of obtaining more and better 

 evidence, I abstain from further remarks. 



A remarkable exhibition of a sand-rock with pebbles occurs in 

 i litis against the Thames at Clifden Ferry. It is traversed by oxide 

 of iron in nests, laminae, and veins running in various directions. 

 As far as the composition of the mass is concerned, this sand-rock 

 resembles somewhat the Shotover irony rocks, and somewhat the 

 pebbly Lower Greensand of Farringdon; but no fossils have been 

 found in it. 



From what has been said it is evident that I regard as still doubt- 

 ful and incomplete the evidence according to which Lower Green- 

 sand deposits have been admitted to occupy large areas on the maps 

 of the country near Oxford. The evidence from fossils (certainly of 

 paramount importance in deciding between sands of such variable 



types as those lietween the Kimmeridge Clay and the Chalk) is either 



wanting or appears opposed to the claim of large territory for the 

 Lower Greensand. Dr. Fit ton quotes no fossils near Oxford, and only 

 casts of Kijilimiiii and Coniferous wood from the iron-sands of Bed- 

 fordshire; and the Geological Survey has had only a glance at an 

 Ammonite, which was supposed to be .!. Deshayesii, on the summit of 

 a hill nqar Oxford, from which I obtained quite a different Ammo- 

 nite, apparently of an Oolitic group, with other shells nut such as 



to authorize the adoption of their sandy matrix into the Cretaceous 



I'amiU . 



* Mr. It. Etheridge hat obliged me with ilii- notice of hu Bearoh. 



