WIESE (CILIVMAS ZINVO) IBACOTINE IRIL(QELGS, IB ING: 725 
“cliffs.” A careful comparison of the cliff masses however with 
the exotic blocks showed that the two are the same. In point 
of size as well as facial development no distinction could be 
established between them, for the same strata containing the same 
fauna occur in both and in point of bulk the exotic block masses 
were found to occur in all sizes up to those of the smaller cliff 
masses. In the accompanying map the distinction between the 
two is a purely arbitrary one, the attempt being made simply to 
indicate the masses previously recognized as ‘‘cliffs”’ in the lit- 
erature of the subject for convenience in discussion. 
Fiistorical_—Betore proceeding to the results of my own studies 
I may introduce a brief sketch of previous work. On account 
of the scarcity of fossil remains in them the Swiss cliffs were 
long thought to be in some unexplained way mere abnormal 
developments of the strata of the adjacent chains and to be 
therefore of Cretaceous age. The petrographic similarity of one 
of the cliff strata now known to be Jurassic, to the Swiss Creta- 
ceous Seewenkalk gave color to this idea. In 1875 Professor F. 
J. Kaufmann succeeded after long and patient search in discov- 
ering a set of fossils which proved beyond all doubt that the 
cliff masses on the Lake of Lucerne (Mythen, Buochserhorn, 
Stanzerhorn, and also the group to the southwest by Giswyl) 
contained a strata of Jurassicage.* Subsequent studies especially 
those of Stutz? have confirmed this and added to our knowledge 
of the fauna. The group of cliff-like masses to the east of the 
Mythen Iberg (see map) were at this time not recognized as 
belonging to the cliffs, as Kaufmann had in 1871 after a brief 
reconnoissance declared them on stratigraphical grounds to be a 
transition deposit between the uppermost Cretaceous and the 
base of the Jurassic. In 1889 Professor Steinmann upon further 
examination compared the strata here found in part with the 
Trias and Jura of Algau in the East Alps and held them to be 
of corresponding age. My own studies in 1891 and 1892 con- 
tF. J. KAUFMANN, Fiinf neue Jurassier, Jahrbuch des Schweits. Alpen Clubs, 
XI. Jahrgang, separate. 
2SruTz: Das Keuperbecken am Vierwaldstattersee, Neues Jahrbuch, 1890, 
II., p. 99. 
