140 Geological Society : — 



their mineralogical contents the dark bands consist of diorite and 

 the white bands of granite. 



The author considers that portions of this group consist, like the 

 hornblende schists, of converted ash-beds, but that other portions 

 are composed of intrusive diorites of later date, the quasi -bedded 

 appearance of both being due to the injection of granite. He 

 pointed out that the quasi-banding is very irregular in its cha- 

 racter, that the bands inosculate, bifurcate, and entangle them- 

 selves in complicated meshes inconsistent with the idea of regular 

 banding, and that they are deflected by the blocks of serpentine 

 imbedded in the dioritic portions of the granulitic rocks as well 

 as by the porphyritic crystals of felspar contained in the latter. In 

 certain places, as on the foreshore at Kennack Cove, the intrusive 

 character of the granitic veins is undoubted, as they cut through 

 the diorite in all directions, but they graduate into bands of normal 

 character. The author considers that the process of injection 

 was aided by the plasticity of the " granulitic " beds induced 

 by the neighbourhood of igneous masses ; also in the case of sub- 

 marine ash-beds by the planes of sedimentation, and in the case of 

 intruded sheets of diorite by the foliation parallel to the bedding, 

 the intrusion of the granite being subsequent to that of the diorite. 



At Pen Voose a foliated granite, the author pointed out, occurs in 

 association with a non-foliated gabbro and diorite, a fact indicating 

 in his opinion that the foliation of the granite was produced before 

 its perfect consolidation. The granite was the last to appear in the 

 order of time, and had the foliation of the granite been produced by 

 pressure after cooling, the gabbro and diorite would also have been 

 foliated. 



2. "The Upper Jurassic Clays of Lincolnshire." By Thomas 

 Roberts, Esq., M.A., F.G.S. 



In Lincolnshire it has generally been considered that the Oxford 

 and Kimeridge Clays come in direct sequence, and that the Corallian 

 group of rocks is not represented. The author, however, endeavoured 

 to show that there is between the Oxford and Kimeridge a zone of 

 clay which is of Corallian age. 



Six palseontological zones were recognized in the Oxford Clay. 

 The clays which come between the Oxford and Upper Kimeridge 

 the author divided into the following zones : — 



(1) Black selenitiferous clays. 



(2) Dark clays crowded with Ostrea deltoidea. 



(3) Clays with Ammonites alternans ; and (4) clays in which this 



fossil is absent. 

 The black selenitiferous Clays (1) are regarded as Corallian, 

 because 



(a) They come between the Oxford Clay and the basement bed 



of the Kimeridge. 

 (6) Out of the 23 species of fossils collected from this zone 22 are 



Corallian. 



