38 
SCENERY OF SWITZERLAND. 
Malm, or Upper Jurassic. 
The Malm is characterised by a considerable 
development of Coral reefs, which often attained a 
great thickness. Between the Corals, which in some 
cases still retain their natural position, are many re- 
mains of Sea-urchins, Sponges, Molluscs, and some 
Crustacea, united by calcareous cement into a more 
or less solid rock. They are often beautifully pre- 
served, having been embedded in the soft mud of a 
quiet sea, which extended completely over the Cen- 
tral Alps. Indeed the southern shore of the Jurassic 
Sea must, in Heim’s opinion, be looked for in 
northern Africa. 
The Malm is yellow and white in the Jura, blue- 
black in the Alps; by its hard, bare, steeply inclined 
rocks, and dry sterile slopes, it gives a special char- 
acter to the landscape, while the Dogger, and still 
more the Lias, from their numerous marly layers, 
furnish a very fertile soil. Where Malm is a dark- 
bluish, grey, conchoidal, calcareous rock, it is known 
as “Hochgebirgskalk.” In the celebrated deposits of 
Solenhofen many remains of Insects occur, includ- 
ing a Moth, the earliest Lepidopterous insect yet 
known. 
