1636 
The elements summed up above for the Kalooé fauna do not 
occur in the British Indian devonian, which yielded only a few trilobites 
with which I cannot identify my species. Melocrinus, which according 
to my preliminary examination appears to oecur at Kalooé, is accord- 
ing to the palaeontological handbooks of Zrrrnt, NicnousoN and 
LYDEKKER a silurian-devonian genus and the species Melocrinus typus 
is typical for devonian strata, but the exact determination of species 
being impossible on the spot no certainty as to the age of the fossils 
has as yet been obtained. I have sent the fossils to Prof. Dr. JONKER 
of Delft, who probably later will publish full details. 
Also in South Yunnan (China) devonian is known, the fauna of 
which has been deseribed by v. Loozy in “Reize des Grafen Szechenyi”, 
Bd. 1, p. 682. In North Yunnan Von RrcnrnoreN collected devonian 
fossils, more fully described by Kayser (v. Ricutuoren, China, Bd. IV, 
p. 75). From the Himalayas only an insignificant devonian fauna 
has become known. I leave it to palaeontologists to make more 
elaborate comparisons based on more extensive lists of fossils. 
It is desirable to study the stratigraphy of the strata near Kalooé 
well and thus also to determine the position of the white dolomites. Ihave 
found those chiefly as boulders in the Aloer Karangpoetih, although 
they occur in situ in some places of the river, and therefore I am 
of opinion that the Goenoeng Karangpoetih partly rests on them. 
A limestone with grey-black flints, as occurs on the northern foretop 
of this mountain, I did not find mentioned in any of the descrip- 
tions of limestones of other parts of Sumatra. Mr. J. B, SCRIVENOR 
wrote to me that he did not know this type of rock in Malacca either. 
The author hopes in a subsequent paper if circumstances permit 
to be able to deal more fully with this trilobite ime of Kalooé, 
the discovery of which he only wished to announce in this first 
communication. Pangkalan Brandén, North Sumatra, Aug. 1915. 
Prof. MoreNGRAAFF made some remarks in addition to the preceding 
article. 
Mathematics. — “On the nature of the limiting surface for mul- 
tiple space transformations.” By Dr. K. W. Rourerrs. (Com- 
municated by Prof. Jan p Vries). 
(Communicated in the meeting of February 26, 1916). 
1. If r+ 1 surfaces of order p are given by means of the 
equations /,=0,..., f-41=0, an r-fold infinite linear system S, 
of surfaces, determined by these 7-+- 1 surfaces, is represented by 
WS; IE Na Ie Petes at Arta Sra 0; 
