Hey Mark, the List looks cool. Having three big boy dinos for Thunderlizard and a well protected Slann will ensure some fun times.
Maybe you could think about running your Carnosaur as a "Scar-Veteran on Carnosaur", its as good as your Oldblood, but 40 points cheaper.
Also, the Skinks don't utilize being Coalesced much. Dropping them, plus the 40 points would allow you to include a unit of Saurus Knights, or to run 2x20 Saurian Warriors instead of the 30, given you got the models (although iam sure most players wouldn't mind you played your Skinks as Saurians in some mixed squads).
Eventually, an army like this, could easily transition into being played as the Koatls Claw subfaction, so you get another playstyle for free!
Overall, good job on your first List. Games including Dread Saurians are always fun for all involved.
May the Dice be always in your Favour.
