88 DONALD C. BARTON 
MAJOR STRUCTURES 
HERCYNIAN RIDGES 
A broad Hercynian (northwest-southeast) ridge through Land- 
shut is suggested by the results of the torsion-balance survey, which 
partially corroborate the northwest-southeast positive anomaly on 
Schiitte’s map of the Bouguer anomalies from the pendulum deter- 
minations of gravity in southern Germany. The B. M. I. torsion- 
balance survey mapped the presence of a broad, somewhat complex 
northwest-southeast maximum through Landshut which would cor- 
respond with the Landshut part of that maximum on Schiitte’s map.® 
The B. M. I. torsion-balance and magnetic surveys indicate that the 
anomaly at Ingolstadt is produced by sharp local structure and sug- 
gest that the Ingolstadt and Landshut anomalies should not be con- 
nected, until further evidence indicates an actual connection. From 
the few data, the writer would infer that the Landshut ridge does ex- 
tend northwestward but that it probably crosses the Danube some- 
where east of Ingolstadt. 
_ The results of the magnetic survey do not suggest the presence 
of the Landshut ridge. 
The results of the two types of surveys seem to indicate: (1) that 
deformation of the crystalline basement is not sufficient to produce 
an appreciable effect in view of the great depth of the basement, and 
(2) that the Mesozoic formations and perhaps the surface of the Meso- 
zoic basement under the Tertiary formations must be deformed suffi- 
ciently to affect the variation of gravity at the surface. The torsion- 
balance data of the single traverse are rather scanty for much inter- 
pretation of the ridge. 
The results of the torsion-balance survey suggest that there may 
be a parallel and similar ridge through Augsburg. 
REGENSBURG SYNCLINE 
The southward prolongation of the Regensburg syncline under the 
Tertiary formations is suggested by the results of the single torsion- 
balance line eastward from Landshut to Landau. A trough of mini- 
mum is shown by Schiitte’s map of the Bouguer anomalies as lying 
in front of the Bohemian massif. North of Regensburg, the minimum 
tends to coincide approximately with the faulted Regensburg syn- 
cline. The results of the torsion-balance survey tend to corroborate 
the presence of that trough of minimum in the Landau area. 
The results of the B. M. I. magnetic survey do not reflect the 
presence of the syncline. 
*K, Schiitte, Karte der Schwereabweichungen Stlddeutschland (Munich, 1930). 
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