258 Mr. J. Lycett on the Upper Lias of Gloucestershire. 



fossils could be procured was very inconsiderable. In descend- 

 ing order occurred — 



* Several feet of blue clay, with intercalated thin layers of dark- 

 coloured shale. 



A thin stratum of grey, finely laminated shale, with clusters 

 of valves of Posidonia Bronnii. 



Brown and blue clays and marly bands containing some irre- 

 gular layers of hard shale, and of thin bands of blue argil- 

 laceous limestone. 



Fossils were moderately abundant in the bands of limestone. 

 Ammonites bifrons was the most conspicuous ; A. communis was 

 in much smaller numbers ; the few other Ammonites obtained 

 consisted of A. falcifer, A. heterophyllus, A. cornucopice, A. eras- 

 sus, A. Lythensis, A. Jurensis, and a new species near to A. 

 Humphriesianus ; a few fragments occurred apparently of Nau- 

 tilus sinuatus, and a single specimen of N. latidorsatus. Belem- 

 nites were comparatively few, as were also Gasteropoda and Con- 

 chifera; the latter included two undescribed species, one of 

 Tancredia and one of Placunopsis. 



In the lower beds bluish -grey clays predominated; but the 

 sections were insufficient to expose an unbroken sequence of the 

 lower beds, although the entire thickness of the stage was ascer- 

 tained with a near approach to accuracy ; the measurement gave 

 a thickness of 105 feet, the beds being free from disturbance. 

 Some few layers of limestone nodules occurred, but their amount 

 was not comparable with those obtained from the Upper Lias of 

 Somersetshire. To the same general deficiency of lime, as 

 exemplified in the paucity and thinness of the limestone bands, 

 may probably be attributed the general scarcity of fossils when 

 compared with the Upper Lias of Somerset ; here the chief mass 

 of the deposit consisted of brown and blue clays which were 

 quite destitute of fossils ; no remains of Saurians or of Fishes 

 were observed. These conditions present a remarkable contrast 

 to the same stage at Ilminster, with its pale yellow limestone 

 charged with Saurians, Fishes, and a multitude of Mollusca of 

 all classes, numbering probably more than 150 species, notwith- 

 standing that the entire thickness of the stage is only a few feet 

 at that place. To study these, the extensive collection of Mr. 

 Moore, in the Bath Museum, should be visited. 



The occurrence at Nailsworth of finely laminated shales with 

 the little Posidonia Bronnii in the upper portion is interesting, 

 as identifying the stratum with the continental representative of 

 the same shale : this fragile bivalve appears to be limited to the 

 single stratum indicated. 



The large Tancredia is the first recorded example in the Lias 



