LA TOUCHE : GEOLOGY OF NORTHERN SHAN STATES. 



usually beautifully preserved in these casts, when first exposed, but 

 they are in so soft a condition that the slightest touch will destroy 

 them, and the greatest care is required to preserve the specimen. 

 Detached eyes of trilobites are also very common in some places, 

 showing the details of the lenses in great perfection, but in the 

 same soft condition, though the other parts of the animal are 

 generally more solid and capable of being preserved in a collec- 

 tion. 



On the western side of the plateau these beds occupy a large 

 area, extending northwards from a line drawn 

 scarpof plateau. ^ estcin along the base of the hills north of Maymyo to 

 the head of the Sedaw valley near Sakangyi, 

 (E 5) as far as the Memauk-Aunglok spur. Throughout this area the 

 beds, as seen in numerous outcrops, are generally tilted up at high 

 angles, or are vertical, and it seems at first 

 Great apparent thick- gigllt ag fl^g^ t ^ e formation must be of 



I16SS. 



very great thickness ; but where it is exposed 

 on the face of the great 2,000 feet scarp north of the Memauk 

 spur, it is seen to be at the most from 700 to 1,000 feet thick, 

 and it appears possible that the prevalence of high dips in the 

 southern part of the area is due either to 'creep ' along the steep 

 hill sides ; to weathering out of the 'cleavage ' lines ; or, what 

 is more likely to be the true explanation, to a general compres- 

 sion of these soft strata between the harder rocks under and 

 overlying them into a series of minor folds and contortions, which 

 cannot be recognised as such on the ground because of the 

 small extent and superficial character of the outcrops. 



In this area collections of fossils were made at the following 

 Fossil localities places :• — At the head of the Sedaw valley, 



on the path from Ani Sakan railway station 

 to Sakangyi (Loc. 85, B 5), besides cystidean plates, a doubtful 

 specimen of EscJiaropora sp. was obtained. Further east, at the 

 top of a small hill immediately north of the village of Nankat, 

 near Letkaung (B 4), Plcetambonites sericea Sow. and Orthis irra- 

 vadtca Reed, both lower Naungkangyi forms, were the only two 

 recognisable fossils collected ; but a short distance further to the 

 north-east, near the village of Ledet (Loc. 82, B 4), in some 

 lavender coloured shales, Leptcena (?) ledetensis Reed, already recorded 

 as occurring at Lebyaungbyan (p. 77), Plectambonites quinque- 

 ostata McCoy, OrtJiis irramdica Reed, and two trilobites, Remo- 



