188 GEOLOGY OF THE ISLE OF WIGHT. 



Some localities of the Island are extremely 

 prolific in organic remains, and have yielded to 

 the researches of Capt. Ibbetson an interesting- 

 series.* J. M. Saxby, Esq. of Bellevue House, 

 has recently collected many species from Bon- 

 church and Ventnor. A list of the fossils obtained 

 by Dr. Fitton from these strata, chiefly from the 

 cliff at Western Lines, is given in Geol. Trans, 

 vol. iv. p. 202. 



The galt. — This is a deposit of very dark 

 blue marl, having an average thickness of 100 

 feet ; the clay in many places has a large inter- 

 mixture of green sand, and is traversed by thin 

 layers of red marl. It presents no distinctive 

 mineral aspect, but is characterised by the abun- 

 dance, peculiarity, and state of preservation of its 

 fossils. Numerous species of Ammonites, Hamites, 

 and other cephalopoda, with their nacreous shells 

 entire, and bivalves and gasteropodous univalves 

 seldom, if ever, found in the strata above or below, 

 may be collected from most localities where the 

 Gait is exposed in natural or artificial sections of 

 any considerable extent. This deposit is seen on 

 each side of the anticlina.s on the southern coast, 

 and in some parts of the Undercliff, near Ventnor 



* There is a pood suite of marl fossils belonging to this gentleman exhi- 

 bited in the Isle or Wight model-room of the Polytechnic Institution of 

 London. 



