Material illustrating detailed structure of graptolites has been etched from limestone by means of hydrofluoric acid.

表明笔石详细构造的物质是利用氢氟酸从石灰岩中侵蚀出来.

辞典例句

These provide base for the correct measurement and valuing of graptolite reflectivity.

从而为笔石反射率的正确测定和取值奠定了基础.

互联网

The black graptolite shale facies indicate a deep - water, half enclosed and anoxic sedimentary environment.

中奥陶世黑色的笔石页岩为典型的半封闭缺氧的深水沉积环境,反映了海水逐步加深,水体也变得相对宁静.

互联网