Extinct plants having tall arborescent trunks comparable to or more advanced than cycads ; known from the pennsylvanian ; probably extinct since the mesozoic .
已绝迹,树干高大,乔木状,与苏铁类相仿或更为进化;首先发现于宾夕法尼亚纪;可能自中生代起灭绝。
The letter surfaced in a pennsylvanian university mailroom earlier this month .
在这月初这封信上写着的地址是宾夕法尼亚大学的某个邮箱。
The letter surfaced in a pennsylvanian university mailroom earlier thellos month .
在这月初这封信上写着的地址是宾夕法尼亚大学的某个信箱。
A 55-year-old pennsylvanian coal miner consults his physician about increasing respiratory distress .
一位55岁的宾夕法尼亚州煤矿工人因呼吸日渐困难而来看医生。
Diagenesis at modern unconformity : pennsylvanian sandstones , grand ledge , michigan .