Hello Dear,
In the 14th September 2017 I found this armor plate from agnathan and found out that it belongs to Ohesaareaspis, the cephalaspid ostracoderm from Late Pridolian Ohesaaare stage,
end of Silurian. I found it it Varena town, South Lithuania, it was in dolomite erratic. Its length is 1,3 cm and it has very interesting surface texture of tubercles.
The genus was not identified in Lithuanian (Southern Baltic region) erratics till now, please vote if you are interested.
Regards
Domas