Traverse I made yesterday (I made it something sililar to traverse on one of the photos of defences near Malakoff Tower)
Traverse like it is in Totleben's Atlas of defences of Sevastopol and as traverses are on most photos.
One of merlons (the wall between two embrasures), there will be a lot of them, with different sizes and shapes
Embrasure (there will be different types of them, especially for Russian fortifications, because at the beginning of siege of Sevastopol there were no gabions at all, so merlons and embrasures were made of barrels, sandbags and metal cicternes (where sailors on their ships kept fresh water) filled with earth.