LIVONIA — SECTIONS ON THE DUNA. 
51 
Feet. 
Compact grey limestone and shale without fossils 4 
Concretionary limestone ; grey in its upper part, red beneath, and containing a re- 
markable species of univalve of the genus Rofella, together with a Natica 8 
Red compact limestone ® 
Marly limestone and shale with red spots 12 
27 
The bed above spoken of as characterized by univalve shells, affords us the 
means of knowing, that nearly the same strata are prolonged by undulations from 
north to south, across the whole of Livonia. Thus higher up the Diina, at the 
Castle of Selburg, and at the country-house of Stockmanshof, we meet with the 
four beds indicated at Kirchholm, including the limestone with the univalves ; 
and the only addition is a greenish blue shale, the lowest bed visible, which is 
brought in by an increase of flexure. At the Castle of Selburg, the cliffs , upwards 
of seventy feet high, exhibit very clearly the same succession. 
The picturesque rocks in the environs of the Castle of Kokenhusen particularly 
deserve notice, not merely on account of the thickness of the vertical section 
(speaking of course by comparison), but specially because the beds contain ich- 
tliyolites. The little river Perse, which there empties itself into the Diina, runs 
in a deep gorge, in which many beds of impure concretionary limestone are seen 
to alternate with courses of calcareous shale or marl. These alternating strata, 
occupying a thickness of about 100 feet, repose on a band of arenaceous lime- 
stone, distinguished by impressions of fucoid-like or polypiform bodies, and beneath 
it is a bed of concretionary limestone with marly limestone, in which are remains 
of Ctenacanthus serrulatus (Ag.), and Osteolepis, &c., both of which genera occui 
in the Old Red Sandstone of Scotland. 
An example of undulation, almost amounting to a dislocation produced by anti- 
clinal elevation, occurs on the right bank of the Diina, near the mouth of its tri- 
butary the Evst, where the inferior shale or clay throws off the calcareous flag- 
stones and marls at an angle of 30° towards the north-east, and at 17° to the south- 
west. 
Concerning the gypsum which occurs in this great deposit, we have nothing to 
add to the notices of Strangways 1 and M. Dubois de Montpereux 2 . It is nowhere 
exposed in the strata upon the Diina, except in the neighbouihood of Kirchholm, 
hut at Diinhof in Courland it is largely quarried. Though no salt-springs have 
1 Geol. Trans., new series, vol. i. p. 11. 
- Karsten’s Archiv. 
