( 142 ) 
appearance. Some pieces of this material are still to be seen in the 
Geological Institute at Groningen. 
Secondly : van Canker’), — when the ramparts near one of the 
gates (Boteringepoort), which ramparts had certainly been made of 
the boulder-clay from the very deep ditches in that neighbourhood, 
were dug off, — found some erratic-blocks consisting of kinds of 
stone such as I never found afterward, and which do not occur in 
the Russian Baltic-Sea provinces, La. slate with graptolites, Faxe-lime 
and sandy glauconite lime-stone with Terebratula lens Nilss. 
Deeper cuts made into the Hondsrug may afterwards give us an 
opportunity of learning whether my original opinion was entirely right, 
or is the true one only as far as the outer layers are concerned. 
I should now like to tell something about the chief Cambrian pieces 
that are found in my collection. L am going to treat only of those 
stones whose age may be more or less precisely determined. 
I. Lower-Cambrian Stones. 
1. Seolithus-sandstone. Eleven stones consisting of this material 
are found in my collection. Nine of them are typical grey, quartz- 
iferous Scolithus-sandstone, showing a peculiar, fatty lustre on the 
side where they were broken off. No layers are visible as long as 
the stone is not changed by the influence of the weather. Only if 
this takes place, the layers become more or less visible. In one stone 
they are rather distinct and turn upward (perhaps downward) near 
the “scolithus.” Two other stones, one of which is blue-grey, whilst 
the other moreover contains red parts, are clearly divided into layers 
and contain much finer tubes than are found in the typical stone. 
In the regions from which our erratie-bloeks come, Scolithus-sand- 
stone was first seen as firm rock in the isle of Runö near Oscars- 
hamm, where according to Torerr *) it was discovered by Dr. Horm- 
strom. Afterwards it was also met with as such by Natnorst *), in 
the isle of Furön, not far from Runö. 
I was wrong when, in treating of the Kloosterholt erratic-blocks, 
I told that Scolithus-sandstone as firm rock is found in Sweden, in 
the neighbourhood of Lund and Kalmar. The same mistake was 
1) Van Carker, Beiträge zur Kenntniss des Groninger Diluviums. Zeitsch. d. 
deutsch geol. Gesellsch. Jahrg. 1884 pag. 718 and 727. 
2) Tore, Petrificata Suecana formationis cambricae. Lunds Univ. Arsskrift. 
Tom. VI 1869 pag. 12. 
5) Narrorsr, Geol. Föreningens i Stockholm Förhandlingar 1879. Bd IV, pag. 293. 
