31. Zhol City ( Xuecheng ), also known as " Snow City ", is located on the lower boundary of the Potala Palace entrance. 32. The lower boundary of abdomen assumes shape of semicircle, and the upper edge of torso with two concave curves becomes regular in form. 33. The Ulangochuian's lower boundary is the approximate base of the Rupelian age and upper boundary is the approximate upper base of the Aquitanian. 34. The lower boundary to the Erfurt Formation is the " Lettenkohlensandstein " in northern Germany and the " Grenz-bone-beds " in southern Germany. 35. Since the lower boundary of the atmosphere is ill-defined, the pressure level of 10 K, is commonly treated as the base of the troposphere. 36. The lower boundary has been defined as the erosional base of the first prominent sandstone above the Ardley coal zone of the Scollard Formation. 37. The lower boundary of a zone in which plinthite occurs generally is diffuse or gradual, but it may be abrupt at a lithologic discontinuity. 38. The eon's lower boundary or starting point of 4 Gya ( 4 billion years ago ) is officially recognized by the International Commission on Stratigraphy. 39. Due to the lower density of the partially molten material, it rises through the wedge until it reaches the lower boundary of the overriding plate. 40. It uses " flex fences " to set the upper and lower boundaries of supply against a definition of the current daily rate of demand.
