help with a plant species

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ive been away on a surprise trip so i haven't been on lately or finished those request which i will do but anyway i went digging for trilobites from the whaleress shale from about 507 million years ago. ive found 70 trilobites fossils with multipull of them in each one. i found a soft bodied naraoia compacta wich is very rare and sells online for 500. but there is a plant species that i dug up and alot of plants back then look like kelp or sea weed singled celled organisms. but this looks like something we see today. but i found int buried with the trilobites by a big mudpit were trilobites got stuck in and died. can anypony help me figure out what species this is