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TWENHOFEL: EXPEDITION TO THE BALTIC PROVINCES. 307 
than corals. Brownish limestones with thin calcareous shale partings 
succeed and at the top is a coral limestone, made up almost wholly of 
these organisms. This coralline limestone, according to Schmidt 
and Mickwitz, affords an excellent datum plane, which can readily 
be followed throughout the entire district. Eastward it is said to 
undergo dolomitization. About a mile west is a new quarry which 
during the summer of 1914 was in operation, and where fossils are 
more readily obtained. The lithology is about the same as the middle 
portion of the Borkholm section and about six feet are exposed. 
Near Herkiill, northwest of the dwelling and on the east side of the 
post road, is a small quarry in the Borkholm. Here the basal ex- 
posures consist of a fossiliferous, crystalline gray limestone with 
mammillary upper surface. Then follow fifteen inches of black shale, 
containing fucoidal impressions, and above this three feet of crystal- 
line, coralline, and crinoidal limestone with many poorly preserved 
coral heads. The beds of this limestone are from two to ten inches 
thick. 
The Herkiill locality made known by Schmidt lies southwest of the 
dwelling, and the former exposures were made by a drainage ditch. 
At the north end of this ditch Schmidt noted the occurrence of the 
white Borkholm limestone in place. This is overlain by what appear 
to be thin-bedded limestones and shales which carry an abundance of 
fossils. No rock is visible in place, but the debris from the ditch has 
been stirred by plowing and the fossils are readily collected. Both 
fauna and lithology are similar to that of the locality described in the 
next paragraph. Schmidt further stated that the contact between 
the Silurian (Jérden Schicht) and the Borkholm could be seen here, 
the Jorden strata appearing at the top of the ditch near its midlength. 
_ Nothing of this is now visible. 
The Nyby exposures, north of Hapsal, are the best that were seen 
of the Borkholm formation. The quarries are situated on a low 
terrace north of the residence of the Nyby estate, and are readily 
found by their nearness to an old stone windmill. 
The section exposed in these quarries, given from the summit 
downwards, is as follows: — 
1. Impure, dark gray, semicrystalline limestone in four to six inch 
beds, separated by thin beds of gray shale. In places 50% of the 
limestone consists of the stems of large crinoids. Four feet six inches. 
2. Impure, dark gray, poorly crystalline limestone (beds four to 
six inches thick) and thinner beds of gray calcareous shale. ‘Two feet. 
Fossils are extremely common throughout, particularly corals 
