1863.] DAY LIAS OF DORSETSHIRE. 289 



is a series, 180 feet thick, of grey marls, which are micaceous, but 

 without sand. Capping these, in Down Cliffs, is the Starfish-bed, 

 above which begin the Middle Lias Sands ; at first these are very- 

 argillaceous, but higher up, and over the intercalated band of blue 

 marl, they become more purely siliceous. This mass of sand, above 

 and below the band of marl, is altogether 170 or 180 feet in thickness. 

 A great clay-deposit next succeeds, the lower 20 feet of which belong- 

 to the Middle, and the remaining 70 feet to the Upper Lias; the boun- 

 dary of the two divisions, as T before explained, being discoverable in 

 an intercalated band of stone. Over the clay-deposit, I include in 

 my section some 150 feet or more of siliceous sands, densely charged 

 with nodules, the highest tiers of which are slightly calcareous, and 

 capped by a solid bed of stone containing also some proportion of car- 

 bonate of lime. These latter, the Cephalopoda-beds, underlie another 

 formation. 



§ III. Distribution of the Organic Remains. 



1. The Belemnite-beds. — The lower portion of the great mass of 

 marl without mica includes these beds, in some of which Belemnites 

 occur more abundantly than in any other bed of the Lias ; in the 

 words of De la Beche, " seams composed of little else than their re- 

 mains are seen on ledges, dry at low tide, at the foot of the Golden 

 Cap." The lowest portions of these beds contain chiefly the Belem- 

 nites longissimus, Miller, but in the higher ones many species are 

 intermingled ; and it is more especially these higher beds, imme- 

 diately underlying the Belemnite-stone, and that band itself, which 

 deserve attention. In the beds below, excepting Belemnites, fossils 

 in a recognizable form are rare ; compressed Ammonites and their im- 

 pressions are abundant, but not in a state to be of much service to 

 the palaeontologist. I cannot therefore pretend to give any precise 

 information as to the characteristic Ammonite of this zone. I believe, 

 however, that fragments of A. Henley i, Sow., do occur throughout 

 it. In the Belemnite-shales and -stone, however, there is an abun- 

 dance of recognizable fossils. The only place where anything like 

 a full and speedy insight into the contents of these beds can be ob- 

 tained is on the beach between the Golden Cap and Seatown when 

 a favourable wind has cleared away the shingle which generally 

 conceals them. Belemnites elongatus, Miller, is, perhaps, the most 

 common form. Another very frequently occurring species is B. 

 clavatus ; but I suspect that some, at least, of the specimens known 

 by this name are only the young of other species. B. longissimus, 

 Miller, is also a form of frequent occurrence. Of other varieties 

 there would appear to be many ; but, in the present state of our 

 knowledge regarding these fossils, I may be excused from venturing 

 on further determinations. One fossil, however, found in the stone, 

 calls for special investigation. I allude to the fossil figured and de- 

 scribed by De la Beche (Geol. Trans. 2nd series, vol. ii. pi. 4. fig. 4) 

 as an Orthoceras *. My specimens indicate that it is more closely 



* In his 'Report,' p. 224, De la Beche records it again as " Orthoceratitea ? 

 elongatus" 



