SECTION AT HOEDWELL CLIFFS. 573 



estuarine series . commence at the lignite. The lignites, again, 

 are much more likely to be freshwater, since they contain leaves 

 and rushes, which seem to have been deposited in still and stagnant 

 water. 



(2) Pale grey clay, with rootlets, 1 foot. 



(1) Lignitic bed, 2 inches. We make this lignite the base of our 

 Freshwater series or Lower Headon. Below commence the Estuarine 

 beds, which have been called " Upper Bagshot Sands " by the Geo- 

 logical Survey. Prom the time of Searles Wood and Dr. Wright, 

 and their contemporaries, their estuarine character has been re- 

 cognized. 



The total thickness of the freshwater Lower Headon we have 

 here measured as 83 J feet. In Totland Bay and Headen Hill we 

 estimated the thickness of the same series as 87 feet. At Hordwell 

 there are not so many Limncea-limestones as at Warden Cliff; but 

 the deposits are much richer in vertebrate fossils than in the Isle of 

 Wight, and the Lower beds are much richer in fossils of all sorts 

 than at Headon Hill. Vertebrates have, however, been found in 

 the Lower Headon of Headon Hill : we may refer to the jaw of 

 Diehodon cuspidatus, Ow., found by Dr. Wright and described by 

 Prof. Owen *. 



We will now proceed in descending order with the measurements 

 of the individual beds of the Estuarine series. At the commencement 

 they are so rich in fossils that they are worthy of separate mention. 



(a) Dark grey to black laminated clay, 10 inches. Neritina 

 concava, Cerithium var labile, 0. pyrgotum, Melanopsis fusiformis, 

 Dreissena Brardii, Cyrena cycladiformis ? 



(b) Mottled green and grey sandy clay ; the grey portions rami- 

 fying in the green in tubular shapes, 1 foot ; rich in fossils : — Oliva 

 Branderi, Ger. var labile, C. pleurotomoides, Natica labellata, Melania 

 hordeola, Melanopsis fusiformis, Marginella simplex, Cyrena cycladi- 

 formis. 



(c) Dark grey to black clay, with grey sand-layers, 1 foot. Possils 

 abundant — Coprolites, Melania murlcata, M. hordeacea, Cerithium 

 pyrgotum, C. ventricbsum, Dreissena Brardii, Modiola Nystii. 



(d) Grey sandy shell-rouk, about 1 foot thick, full of fossils — 

 Cerithium pleurotomoides being excessively abundant. Many years 

 ago one of the authors found three turtles in this bed ; they were 

 whole when found, but could not be preserved. 



These beds (a-d) apparently correspond to the lower part of No. 16. 

 of the Marchioness's section, 4-5 feet. She mentioned that they are 

 generally covered with beach ; but the sea having swept the beach 

 away in August 1851, what had not been seen for years was dis- 

 covered. We may add that we were equally fortunate in August 

 1882. The crowding of the fossils in places is extraordinary. The 

 beds were measured by us at Long Mead End. 



(e) Whity-brown to pale yellow sands, with some ochreous seams ; 

 a layer of Cerithium, pleurotomoides at the base. 



(f) Pale grey sand full of Cerithium pleurotomoides, ochreous colour 



* Quart. Journ. Geol. Soc. vol. iv. p. 36. 



