STRATIGRAPHY OF SHAN-TUNG. 45 
conspicuous because of their color, traverse the rock. Of exceptional 
occurrence are certain scattered strata of earthy gray limestones and 
partings of gray calcareous shales. These, however, constitute but a very 
small part of the whole formation. 
Fossils in the Tsi-nan formation.—Fossils are rare at any horizon and 
are usually entirely absent. Where found at all they occur as siliceous or 
calcareous casts upon the weathered surfaces, or are visible in section 
only. When the rock is broken the fracture disregards the outlines of 
the fossils, and it is therefore futile to search for them, except where they 
have been etched out by weathering. The only identifiable fossils found 
in this area are referable to the Ordovician period. About 700 feet, 210 
meters, above the base of the Tsi-nan formation imperfect specimens of 
Orthoceras sp. were found. Similar forms were collected at indeterminate 
horizons in the hills southwest of Tsi-nan-fu. A brachiopod related to 
Strophomena was obtained at one of these localities. 
IN THE SIN-T’AI DISTRICT. 
Stratigraphy.—So uniform is the main body of the Tsi-nan formation 
that little need be said of its facies in the Sin-t’ai district as contrasted 
with that of the Ch’ang-hia district. The lower member exhibits less 
variation than before, being a fairly constant succession of ashy white 
limestones, with local layers of crystalline dolomite and gray calcareous 
shales. A minor structural peculiarity of these gray limestones serves to 
distinguish them from other Shan-tung formations in almost all situations. 
The rock is crossed by numerous cracks or “blind joints’’ in two systems, 
which are perpendicular to each other, and the agents of weathering, etch- 
ing along these planes of weakness, divide the surface into little squares, 
usually about 1 centimeter in breadth. This checkered appearance is 
one of the most prevalent characteristics of the lower Tsi-nan limestones. 
Fossils in the Tsi-nan.—The massive upper limestone, which outcrops 
at Ts’ai-kia-chuang, in the hills south of Sin-t’ai and around Yen-chuang, 
needs no further description. After painstaking search, fossils were found 
in the first locality, not far below the top of the formation; they included 
undetermined gastropods, Orthoceras, and a trilobite (Asaphus?) which 
could not be extricated from the large slab of limestone in which it was 
embedded. Loose rubble resting upon these outcrops near Ts’ai-kia-chuang 
yielded the following imperfectly preserved Ordovician forms: 
Brachiopod (Orthis ? or Dalmanella ?) Orthoceras sp. undt. 
Lophospira sp. undt. Asaphus? sp. 
Gastropod (Maclurea or Helicotoma) 
