Page:The Habitat of the Eurypterida.djvu/173

Rh :Eurypterus sp.
 * Pterygotus bilobus ? (Salt.)
 * Lanarkia horrida (Traq.)
 * L. spinosa (Traq.)
 * L. spinulosa (Traq.)
 * Slimonia acuminata (Salt.)
 * Stylonurus sp.
 * Thelodus scoticus Traq.
 * Ateleaspis tessellata (Traq.)
 * Ceratiocaris sp.
 * Birkenia elegans (Traq.)
 * Lasanius problematicus (Traq.)
 * Plants
 * Sponge

2. The Anticline of the Hagshaw Hills. About five miles to the south of the Lesmahagow anticline rises the crest of the Hagshaw Hills anticline, the axis trending northeast southwest. The area between the two anticlines is occupied by a northern belt of limestone, Mississippic in age (Calciferous limestone of Scottish geologists), and by a southern area of Lower Old Red sandstone with one patch of Upper Old Red. Rising above these is the anticline forming the Hagshaw Hills, where the Wenlock, Ludlow and Downtonian are exposed by erosion. It is only in the northern limb of the anticline that the Wenlock and Ludlow are visible, for the southern has been cut off by a thrust fault along the plane of which the older Siluric rocks have been brought to rest against the younger ones. The Douglas Water and its many small tributaries have exposed a number of good sections in the western area of the anticline. One of the best of these is in the Ree Burn, south of the Glenbuck Reservoir where there is an almost continuous section of the Ludlow rocks. At one point in certain blue finely bedded shales and flaggy greywackes specimens of Ceratiocaris, Slimonia and Beyrichia kloedeni, have been found. Along the southeastern slope of the anticline where the Podowrin Burn joins the Douglas Water near Monksfoot a transverse section of the Ludlow rocks is shown. They are greywackes and flaggy shales and are thought to be the equivalent of the lowest Ludlow in the Lesmahagow area. It has not been possible to obtain any definite statement as to the exact horizons in which the fossils occur and whether the eurypterids occur as they