26 RESEARCH IN CHINA. 
appearing in all sections examined, but the majority are of local development 
only. Fossils occur very sparsely in the shales and are usually not well 
preserved; but in the limestone layers and nodules they are often abundant, 
and, although fragmentary, are clear and distinct. In some layers the sec- 
tions of the fossils, which appear on the weathered surfaces in great profusion, 
give the rock a streaked and spotted appearance which is striking. The 
upper Man-t’o faunas are rich in trilobites and brachiopods, which are in 
a general way similar to those of the North American Middle Cambrian. 
The transition from the Man-t’o shale to the overlying Kiu-lung lime- 
stone is usually marked by a few feet of interbedded shales and slabby 
limestones, upon which the massive strata of the cliffs rest conformably. 
Fossils from Man-t’o shale.—No fossils whatever have yet been found 
in the lowest 30 meters or more of the Man-t’o formation. About 36 to 
45 meters above the base there is a thin member of fossiliferous slaty black 
limestone, which is associated with buff and brown calcareous shales and 
is constant over the whole district. On the hard black slabs fragments 
of a large trilobite are almost always preserved. ‘This is Redlichia chinensis 
Walcott, a form closely related to the genus Olenellus. One rarely finds 
anything but spines and pieces of the free cheeks, but here and there an 
imperfect cranidium may be discovered. ‘The fossils are visible only on 
the weathered surfaces, and it is therefore useless to split the rock open. 
Excepting an undetermined species of Redlichia and certain indetermi- 
nate fragments, no other fossils have been recognized at this horizon. 
In the overlying portion of the formation fossils appear occasionally, 
but it is rare to find them in considerable abundance. ‘The lowest horizon 
yet discovered is about 15 meters above the Redlichia limestone; it is the 
lowest of that succession of thin gray crystalline limestones, which is so 
characteristic a feature of the upper part of the Man-t’o shales. The 
stratum is usually only about 6 meters thick, and yet it is constant over 
most of this district. The fauna collected from this limestone presents little 
variety, but the individual fossils are rather abundant: 
Ptychoparia mantoensis Walcott Ptychoparia ligea Walcott 
A similar gray limestone, only a few feet thick, forms a ledge in the 
slopes of shale about 25 meters above the last horizon mentioned. ‘This 
contains abundant, although fragmentary, remains of several trilobites 
and one brachiopod: 
Billingsella richthofent Walcott Ptychoparia aclis Walcott 
Ptychoparia mantoensis Walcott Unidentified trilobite fragments 
The upper part of the formation, consisting of two thick beds of dark 
sandy shales with thin, gray limestones, frequently contains small, disk- 
shaped nodules of limestone, stained a deep, maroon color by iron oxides; 
