Impressive thing... Lucy has been working on some benthic graptolites recently (things like tuboids), and as you probably know, there are a lot of genera that could potentially be one or the other. But you know what? Microsctructure can help. If individual tubes show fine transverse banding of the right type (it's got to be really clear) then it's a graptolite.
Having said that, I'm sure Chaetocladus is an alga, although the structure is quite like some tuboids.