50 
DEVONIAN ROCKS IN COURLAND. 
Devonian Rocks in Courland, fyc. — We have already stated our belief (p. 33) that 
Devonian rocks occur beneath the superficial red detritus near the Prussian frontier, 
and in the government of Yilna (see Map). In Courland, however, we are not left 
in any doubt. Argillaceous limestones, spotted red and green, are seen to alternate 
with variegated marls and other beds more sandy, which are exposed on the banks 
of the chief rivers of this province. 
The fine escarpments and the cascade of the river Windau at Goldingen, the 
ancient capital of the province, present strata having exactly the same lithological 
characters as those we have described on the Volkof and elsewhere, and though 
they have not yet afforded organic remains in this locality, there can be no doubt 
of the age oi these strata ; for on following them to Asuppen, a distance not 
exceeding thirty miles (which is inconsiderable where strata ai’e so horizontal), 
they offer the requisite evidences. 
A small river at the country-seat of the Baron Hahn lays bare, beneath the 
alluvial soil, a group of marly, siliceous flagstones, each about half a foot thick, 
alternating with thinner flags. In their upper part these flagstones are of deep 
yellow, greenish, and spotted red colours ; in which respect they are undistin- 
guishable from the rocks of Goldingen, and like which they contain no fossils. 
The lower beds, however, are of a yellow colour, and are loaded with the Spirifer 
Archiaci, a characteristic Devonian species of the Boulonnais. Again, beneath 
these flagstones is a bed of red clay about three feet thick, which overlies a course 
of similar dimensions of a blueish or greenish marly grit, striped with laminee of red 
marl. In these lowest marly laminae we discovered a good number of remains of 
ichthyolites, among which are scales of Holoptychius ?. The beds at this locality 
have a slight inclination of about 3° to the north, and they doubtless participate 
in one of the numerous undulations to which the strata of this horizontal country 
have been subjected, as explained by the section of the Diina above Riga, the 
river which separates Courland from Livonia, and which we now proceed to 
describe. 
Devonian Rocks in Livonia — Section of the Diina. — All the strata exposed along 
the banks of this river in ascending from Riga to Kirchholm and Kokenhusen, 
belong to the Devonian system, and they form numerous undulations, by which 
they are inclined both to the north-north-west and to the south-south-east. For 
example, at the ancient castle of Kirchholm, where the beds are bent into a double 
flexure, there is the following section : — 
