212 Rev. IV. D. Conybeare on a Geological Map of [March, 



Terebratula trigonella, 



Ammonites ammonius, 



Ammonites amaltheus, 



Ammonites hircinus, 



Nautilus coactus, 



Orthoceratitse, 



Joints of encrinites and peutacrinites, 



A species of trilobile. 



Bones of monitors and of fish, a separate line belonging to the 

 vegetable kingdom, leaves of dicotyledonous plants (in which 

 respect there is a distinction between these remains and those 

 of the coal fields which are all monocotyledonous), and frag- 

 ments related to the lycopodium and bamboo, but no true ferns. 



c. The Variegated or neio Red Sandstone exhibits a series of 

 friable sandstones and argillaceous marls, in which a red colour 

 varied by streaks and spots of a greenish-yellow, &c. prevails. 

 The sandstone predominates in the lower members, and is asso- 

 ciated with conglomerate beds. Gypsum and rock salt occur in 

 this deposit as in that of the zechstein. Iron is the only metal, 

 I believe, which it has yet. yielded. 



Distribution. — It is easy to trace generally the distribution of 

 the whole series, but much obscurity still hangs over the exact 

 demarcation of its individual members. This it may now be 

 expected will shortly be dissipated in as far as it arises from our 

 hitherto imperfect knowledge of the structure of the countries in 

 which it occurs, by the publication of the works alluded to in the 

 beginning of these essays ; but in part it results from a physical 

 cause which cannot so readily be surmounted ; namely, the diffi- 

 culty, if not impossibility, of ascertaining in localities where the 

 middle series of limestones (b) may happen to be wanting ; 

 whether the sandstones and conglomerates belong to the upper 

 class (r), or the lower (a) : following the same route which has 

 been traced in the preceding articles, we have first to examine, 



(A.) The Coasts of the Baltic. 



The red marl containing gypsum, which occupies a very exten- 

 sive tract in the centre of Russia, appears to skirt the transition 

 district of Esthonia, near Riga. Its continuation ought to be 

 sought for between the transition and more recent districts in 

 Scania and the Danish isles ; but these districts have not yet 

 been described with sufficient precision to enable us to speak of 

 them with certainty. 



(B.) The British Isles. 



1. It is possible that the sandstones of the Orkneys may 

 either wholly, or in part, belong to this series. 



2. The same observation will apply to those of the Sutherland 

 coast on the north-east of Scotland. 



