tetragraptus मीनिंग इन हिंदी

The lower boundary of the Floian is defined as the first appearance of " Tetragraptus approximatus ", a graptolite species.
The Tremadocian ends with the beginning of the Floian which is defined as the first appearance of " Tetragraptus approximatus " at the GSSP in Diabasbrottet quarry, V�sterg�tland, Sweden.